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Robust retrieval augmented generation

Shu Hao Hoh

DR-NTU (Nanyang Technological University), 2026

Abstract

Retrieval Augmented Generation (RAG) enhances Large Language Models with external knowledge but is vulnerable to noisy and contradictory retrieved content. This study develops a modular framework for evaluating RAG robustness under controlled perturbations. Four QA benchmarks are normalised to a common schema and evaluated across two noise types, four intensity levels and six pipeline variants targeting different stages, producing 192 configurations and 96,000 evaluations. Results demonstrate that robustness gains are stage and noise type dependent: pre-retrieval interventions primarily address retrieval noise while context stage filtering most effectively mitigates contradiction noise. A consistent accuracy–faithfulness trade-off is observed, and combining all interventions produces non-additive interactions that can degrade calibration. Preliminary LLM-based validation confirms these trends transfer to generative pipelines. The findings show that no single intervention is universally optimal, motivating objective aware, stage specific robustness design for RAG systems.

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